Linear-elastic results stress distribution

The commercial finite element program, Abaqus [17], was used to calculate the stress distribution in an edge delamination sample. A fully three-dimensional model of the combinatorial edge delamination specimen was constructed for the finite element analyses (FEA). For clarity, some of the FEA results and schematics are presented as two-dimensional configurations in this paper (e.g.. Fig. 1). The film and substrate were assumed to be linearly elastic. The ratio of the film stiffness to the substrate stiffness was assumed to be 1/100 to reflect the relative rigidity of the substrate. This ratio also represents a typical organic... 

With this linear elastic stress analysis, the correlation between crack initiation and stress distribution has been established. The interfacial cracking occurs at sites sustaining high peel stresses, while the bulk cracking results from the concentration of the equivalent stress. Thus, enhancing either the adhesion to the component or the bulk strength of the ICA joint will help to improve its reliability. 

The effects of adherend yielding were investigated by modelling the adherends with elasto-plastic properties. The adhesive maximum principal stress distributions are shown in Fig. 46 for a case where the adherend properties correspond to a relatively low strength alloy (a 0 -2% proof stress of 110 MPa) and the adhesive is linearly elastic. At a very low load of 0 01 kN the distribution is identical to that in Fig. 45, since the adherends are still elastic. Under the action of tension and bending, the adherends begin to yield at an applied load of approximately 1 5 kN. At 3 kN, the adherend plastic deformation has had two effects on the adhesive stresses. Firstly, it has led to a reduction in the peak stress concentration at the end of the overlap, at point A, over and above that for the elastic case, as a result of the enhancement of... 

For the calculation of the stress distribution in geometrically complex components, the finite element method, Irequently under the assumption of a linear elastic materials behavior, is widely used. If the results of these finite element calculations are used for a fatigue life analysis, the local strength has to be considered. For the assessment of finite element results, with regard to its fatigue strength, the application of the concept of local stresses offers a solution Local S/N-curves are calculated. 

A simple way to illustrate the viscoelastic properties of materials subjected to small deformations is to evaluate the stress that results from combining a linear spring that obeys Hooke s law and a simple fluid that obeys Newton s law of viscosity. An example of such combination is the mathematical representation of the Maxwell element. Even though this model is inadequate for quantitative correlation of polymer properties, it illustrates the quahtative nature of real behavior. Furthermore, it can be generahzed by the concept of a distribution of relaxation times so that it becomes adequate for quantitative evaluation. Maxwell s element is a simple one combining one viscous parameter and one elastic parameter. Mechanically, it can be visualized as a Hookean spring and a Newtonian dashpot in series ... 

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